Effect of Chloride Ion on Soil Corrosion Behavior of Galvanized Steel and Stainless Steel in Jilin Region

Chloride ion（Cl^-） is the most important anion that causes soil metal corrosion. The soil corrosion law of Cl^-and the corrosion resistance of different metals in dark brown forest soil were explored using indoor simulated acceleration experiments. The morphologies and composition changes of metal corrosion products were analyzed using X-ray diffraction,X-ray photoelectron spectroscopy, metallographic microscope and scanning electron microscope. The results show that Cl^-is adsorbed on the surface of galvanized steel to promote corrosion, leading to the dissolution of Fe²⁺. When the content of Cl^-is2.0 mg/g, the self-corrosion current density I_corrof galvanized steel is 78.361 μA·cm^-2and the corrosion is the most severe. Cl^-promote the formation of corrosion pits in stainless steel by replacing unstable O atoms on the surface, and thus a primary battery is formed. When the buried sheet test is carried out for 42 d, the surface corrosion products of galvanized steel are mainly Fe₃O₄, FeOOH and Fe₂O₃. Compared with the galvanized steel, the stainless steel has a larger capacitance arc and higher self-corrosion potential, and it is more resistant to corrosion. The corrosion rate of the galvanized steel is 20 times higher than that of stainless steel.